1. Field of the Invention
The present invention relates to a controlling apparatus for a printer capable of printing in a plurality of printing modes and, more specifically, to a printer controlling apparatus related to an unwinding processing of characters to be printed in respective printing modes.
2. Description of the Related Art
Printers having various functions have been widely used recently. Accordingly, various types can be selected as formats to be printed out. Generally, designation of the format is set based on a control command transmitted together with the data. When the control command is not transmitted, the printing format is designated by a default value of a control command stored in the printer side or by an input from a user.
Generally, a printer controlling apparatus contains a plurality of fonts, and printing is carried out with any of the font designated. The font includes a bit map font in which the font is provided in dots (FIG. 1A), an outline font (vector font) representing only the outline of the font (FIG. 1B) and so on. In the outline font, the outline of the font is represented by a numeral or a mathematical expression. At printing, the outline is drawn at first, and the inside of the outline is painted thereafter. It has an advantage that expansion and reduction of the font can be freely carried out.
In a conventional printer controlling apparatus such as described above, when the outline font, for example, is stored with the data compressed, the time is required for expanding the data, which leads to degradation of the printing capability. If all the fonts are expanded in advance and the expanded data are to be stored in the memory, the necessary capacity of the memory becomes too large.
According to Japanese Patent Laying-Open No. 61-264377, character patterns are compressed point by point or character by character to be stored, and the unwinding process is done from the compressed font data memory to the original character on every specified character or every specified size.
Although the memory capacity can be made smaller in this method, the data must be expanded every time the printing is carried out, so that the speed of operation can not be increased.
The speed of processing is an important problem in the field DTP (Desk Top Publishing) which has been increasingly in demand recently, and expensive hardwares are needed to increase the speed of operation.